The present invention relates to an apparatus for making inclined hollow concrete columns, and more particularly for the continuous moulding of free-standing or self supported hollow concrete columns, the axis of which are inclined relative to the horizontal.
There are known methods and means for the continuous moulding of concrete columns, compact columns as well as hollow columns. In most methods are utilized various designs of sliding formwork. There is thus known sliding formwork for moulding vertical hollow concrete columns, wherein liftable jigs support the formwork and which during lifting define the inside and the outside walls of the column. The formwork serves thereunder for positioning the formwork equipment. In some designs the jig with the formwork is supported and lifted directly from the ground. There is however also known formwork whereby the moulded, partly solidified concrete serves as support for the formwork equipment. In this connection there are utilized preferably hydraulic jacks and rod elements which may form part of the concrete reinforcement and which are imbedded in the moulded concrete wall.
In connection with concrete structures there is frequently a need for inclined hollow columns of concrete. Such columns have hitherto usually been moulded in the vertical position using conventional formwork and thereafter been placed into the desired inclined position. There is known a method for sliding formwork casting of two or several columns at the same time and which thereby provide mutual support.
The problems in connection with the control and/or elimination of prevailing lateral forces in the column and in the formwork in connection with the oblique loads thereon have heretofore not been satisfactorily solved.
The present invention relates to a new Summary of The Invention system for the continuous "in situ" moulding and construction of inclined, free-standing hollow columns of concrete.
A particular object of the invention is to provide systems for the moulding of hollow concrete columns having large dimensions, and particularly destined for use in connection with concrete oil platforms for offshort use and including columns having for instance a diameter of 6 to 20 m and having a height of 100 to 150 m.
The system in accordance with the invention is thus of the kind utilizing sliding formwork, and whereby there is initially provided a base construction and a bottom section of the column anchored thereto. Within the bottom section of the column is positioned a combined support- and guiding means which is displacably positioned, but which is firmly biased against the inside wall of the column and is liftable in a known fashion by being anchored to the moulded part of the column by means of lift jacks or the like. The support-and guiding means are provided with power operated lateral adjustable means such that during the continuous moulding of the column it is possible adjust and control the direction of the moulded column.
The system of the invention may be of several embodiments. One embodiment comprises a carrier dimensioned to be inwardly positioned and guided in the column, which carrier is provided with slides or roller means, such that the carrier can be firmly biased against the inside of the moulded and solidified part of the column. The uppermost part of the carrier is provided with transverse cantilevered beams or yokes protruding laterally outside the column. These beams or yokes are provided with the sliding formwork for the moulding of the inside as well as the outside of the column. Directly above the column wall positioned jacks having lifting elements operable to be anchored into the moulded concrete wall and which serve to carry and lift the entire system.
In a preferred embodiment of the invention there is provided between the carrier and the lateral top support for the formwork a forcibly pivotable support stem operable to provide for the desired positioning and guiding of the formwork. Thus, it is impossible to control of the direction of the column as it is moulded.